Method of producing compound fabrics

ABSTRACT

A method for producing a pile type fabric in which the pile or fleece is sewn on a base fabric with a stitching thread composed of materials having different thermal softening characteristics, so that one of the components bonds the thread to itself and to the base fabric. Another component may have heat shrinkable characteristics within the range of temperatures of the treatment.

United States Patent 1 1 Ploch et al.

[ Sept. 24, 1974 METHOD OF PRODUCING COMPOUND FABRICS [75] Inventors:Siegfrid Ploch, Karl-Marx-Stadt;

Kurt Klinger, Leutersdorf; Joachim Reif, Karl-Marx-Stadt, all of Germany[73] Assignee: Forschungsinstitut Fur Textiltechnolgie, Karl-Marx-Stadt,Germany 22 Filed: Oct. 5, 1972 21 Appl. No.: 295,309

[52] US. Cl 156/93, 28/77, 112/411 [51] Int. Cl 1332b 7/08 [58] Field ofSearch 112/411; 28/77; 156/93 [5 6] References Cited UNITED STATESPATENTS 3,168,883 2/1965 Ploch et al 112/411 Gardner 156/93 3,337,3818/1967 Kuhn 156/93 3,420,731 l/l969 Kuhn 156/93 x 3,649,428 3/1972Hughes 28/77 Primary ExaminerEdward G. Whitby Attorney, Agent, orFirmNolte and Nolte [5 7 ABSTRACT 3 Claims, No Drawings METHOD OFPRODUCING COMPOUND FABRICS This invention relates to a method ofproducing compound fabrics constituted of a pre-formed base fabric ontowhich yarns or other fibrous material, such as a fleece, extendingapproximately lengthwise to the fabric are fastened. In such fabrics thefibrous material extends transversely of, preferably perpendicular orapproximately perpendicular to, the length of the fabric in the plane ofthe fabric, and is sewn thereon by means of longitudinally extendingparallel stitched seams.

The type of fabric to which the present invention re lates is typifiedby U.S. Pat. No. 3,168,883. The present invention represents animprovement in the manufacture of such fabrics.

The method of the invention may be used for the production of liningfabrics, outer fabrics for clothing, imitation furs and other fabricshaving a textured surface. The method is especially suitable, however,for the production of crepe, especially velvet cord, .in which thefloats between the stitched seams are cut and the resultant fiber ribsgive the fabric the configuration of a velvet cord.

The quilt stitched binding between the base fabric and the overlyingyarns or fleece is attained by means of a stitching-knitting machine,such as a Malimo machine. Chain stitch seams are formed which bind thebase fabric to the overlying yarns or fleece.

Heretofore the thread of the seams constituted of a synthetic material,for example a polyamide or polyester, very quickly broke due to hightension or damage by the needles. The resultant parting of the seamleads to disintegration of the compound fabric.

It is an object of the invention to impede breaking of the seams andprovide a method of producing stable, wear-resistant, compound fabrics.

Acording to the invention, a thread for the seams is produced ofcompound filaments and by an additional tightening of the seams damageto the seams and accompanying disintegration of the fabric is fullyavoided.

In order to overcome the above problem, it has been proposed that thethread for the seams be comprised of a monofilament core sheathed with asynthetic material, for example by roll fusing, powder centering orpowder fusing techniques. This solution, however, has been found to beunsatisfactory, in view of the economic considerations involved and alsosince such threads are subject to the blocking effect, i.e., the mutualadhesion of the synthetic sheaths of the threads on the cones, wherebythe processing of the fabric is 'rendered more difficult.

In accordance with the invention, the sewing threads for bonding thefabric are comprised of one or more filaments, the sewing threadsincluding at least two fiber materials having different thermalcharacteristics. Thus, one of the fiber material components has a lowerthermal softening range than the other fiber material component orcomponents. In manufacturing afabric in accordance with the invention,after the seams have been formed the fabric is subjected to a heattreatment to a temperature within the softening range of the componenthaving the lower softening range, so that the component having the lowersoftening range becomes bonded to the base fabric and to the fibrousmaterial sewn onto the base fabric, as well as bonding the thread toitself wherever contact is made between different parts of the thread.In addition, the softening of the thread simultaneously affects theshrinking of the thread, thereby improving the bonding of the compoundfabric.

The sewing thread employed in accordance with the invention may beeither in the form of a single filament, or a plurality of filaments,the term filament being employed herein to refer either to filamentsformed as continuous elements, for example by extrusion, or filamentsformed by the drawing out and twisting of fibers.

The thread for sewing the compound fabric, in accordance with theinvention, may be in the form of a twisted thread including filaments ofdifferent thermal resistance, i.e., the filaments forming the thread area mixture of filaments having different thermal softening andshrinkability characteristics. Alternatively, filaments of two differentthermal characteristics may be disposed closely adjacent each other andintroduced simultaneously into the same guiding element, such as thepuncturing needle of the stitching-knitting machine employed in theproduction of the compound fabric, so that the filaments aresimultaneously introduced into the machine to form a chaimstitch seam.

Very good results have been obtained when unmodified polypropylenefilaments'are employed as one of the components of the stitching thread.While modified polypropylene filaments may be employed, such asfilaments modified to improve their ability to accept dyes, it is ofcourse important that the modification employed does not have an adverseeffect upon the thermal characteristics and adhesive power of thematerial in the plastic deformable state, and the material must thus beselected to avoid such undesirable change in these characteristics.

Mixtures of polyethylene terephthalate and polypropylene filamentmaterials may also be employed as the stitching threads in accordancewith the invention. In order to determine the most desirable stitchingthread, from the standpoint of the relative percentages of polyethyleneterephthalate and polypropylene filaments forming the twisted filamentthread, the two ends of a number of pieces of thread of differentrelative proportions of these materials were fused at differenttemperatures to a'flat piece of a cellulose material, the test pieces ofthreads having legs about lOmm long to form clamps to facilitate thetesting of the adhesive strength of the bond. The adhesive strength ofeach bond was determined by a tensile strength test, the results oftests of various threads composed of filaments of the above materialsbeing tabulated in Table l:

Stitching Thread on the Percentage of Polypropylene and on the ThreadSize.

The strength of the stitching thread is also influenced by the number ofindividual filaments employed in the structure of the thread, and by thetemperature employed in the bonding process. The strength of thestitching thread is further influenced, although to a lesser extent, bythe qualityand quantity of the material employed in the preparation ofthe threads.

Interpolymer filaments may also be employed of one of the constituentsof a stitching thread in accordance with the invention. For example,similar high adhesive strengths are obtained when the filaments of thestitching thread contain between 30 and 70 percent of a vinylchlorideand vinylacetate (85:15) copolymer. While the remainder of the stitchingthread may be comprised of cellulose filaments, the adhesive strength ofthe stitching thread is increased if polyester filaments are substitutedfor the cellulose filaments. Strength tests of such stitching threadsare illustrated in Table 2. In these tests, it is immaterial whether thepolyester component is a polymer of terephthalic acid and ethyleneglycolor l,4-bis-(hydroxymethyl-)cyclohexane (cyclohexanedimethylol-( 1.4) ora copolyester with isophthalic acid or p-oxybenozoic acid as a comonomerconstituent.

Composition of a Twisted Vinylchloride/Vinylacetate-Copolymer filament(85:15) and Polyester Filament Thread.

Polyethylene filament materials may also be employed as one of theconstituents of a stitching thread in accordance with the invention, ifit is kept in mind with respect to the processing and use of suchfilaments that this material melts at temperatures between 110 and 135C.Polyolefin filament materials may also be employed as either the basematerials of the stitching thread, or as the shrinkable and bondingcomponent thereof, in the form of very fine monofilaments ormultifilaments.

As an alternative, the stitching thread employed in the method of theinvention may be formed of bicomponent filament materials of theside-on-side type, the core-sheath type of the matrix-fibril type,provided that the softening of fusing ranges of the polymer componentsof the bicomponent filaments are sufficiently far apart. For example, insuch a structure one component may be a polyethylene terephthalate andthe other a polyolefin or a mixture of two polyolefins having asoftening range between 115 and 175C.

It has further been found that especially tight stitching seams may beobtained if the stitching thread includes thermally shrinkablematerials, such as highly shrinkable polyester filaments, in addition tothe thermally responsive bonding filaments. Further, if it is desired toemploy a stitching thread enabling a particularly bulky seam to fill thepunctured holes in the base fabric, a stitching thread may be employedcomprised of three different types of filaments, such as a thermallyresponsive bonding thread. a thermally responsive shrinkable thread anda textured filament for effecting the formation of the bulky seam.

The heat treatment necessary to effect the desired shrinking as well asthe desired adhesive strength of course depends upon the type ofbicomponent or biconstituent filament material employed.

Synthetic fibers of polyoxymethylene, i.e., polyformaldehyde fibermaterials, also have very favorable characteristics for use as aconstituent of the stitching threads in the manufacturing of bondedfabrics in accordance with the invention. These materials have greatbreaking strength, are not electrostatically chargeable, and cansatisfactorally stand twisting without abrasion. The adhesive strengthsobtained with such materials, depending upon the dwell time at atemperature of 160 to 180C, are satisfactory to meet the requirements ofpractical applications.

The heat treatment in accordance with the invention may employ infraredradiation, or alternatively hot air treatment may be employed.

Several examples of satisfactory stitching threads that may be employedin accordance with the invention are as follows:

EXAMPLE 1 The stitching thread consisted of a twisted thread of apolyester filament 5.6 tex and a polypropylene filament 5.6 tex, thethread having a twist of 350 turns per meter. A bonded fabric stitchwith this twisted thread was subjected, on a stretching frame, to a heattreatment between 165 and 175C at which the polypropylene filamentbecame bondable, effecting the mutual fusing of the meshes of the seamand the fusing of the thread to the bonded fabric.

EXAMPLE 2 The stitching thread is a mixed spun thread of 14 tex,produced by conventional spinning methods and consisting of fibers of amixed polymer on a basis of vinyl-acetate/vinyl-chloride orvinylidenchloride/vinylchloride copolymers, and cellulose fibers such asviscose fibers or cotton. Mixing ratios of 33:67 and 50:50 were used forthe mixed polymer. Bonding of the stitching thread to itself and to thebase occurred with a heat treatment at to 170C, in which range the mixedpolymer fibers became heat bondable.

EXAMPLE 3 The stitching thread consisted of a polyester filament 5 6 texand a bicomponent filament 8.4 tex on the basis of a modified polyesterand polypropylene. Both threads were fed jointly and untwisted by way ofthe same puncturing needle of the stitching-knitting machine. in thisExample, the polypropylene may be crystalline and contain admixtures ofanother polyolefin.

EXAMPLE 4 The stitching thread consisted of a bicomponent orbiconstituent filament l0 tex on the basis of a polyamide andpolyolefin, fusion occurring after a heat treatment at to C when thepolyolefin was a polyethylene. The heat treatment occurred on astretching frame, although an infrared drying treatment alternativelycould have been employed.

While the invention has been disclosed with reference to a limitednumber of embodiments, it is apparent that many modifications andvariations may be made therein, and it is therefore intended in thefollowing claims to cover each such vairation and modification as fallswithin the true spirit and scope of the invention.

What is claimed is:

l. A method for producing a compound fabric of the type having a basefabric onto which a layer of threads or fibers of a fiber fleeceextending substantially perpendicular to the length of the base fabricare fastened by means of parallel seams of a stitching thread; saidmethod comprising stitching said fiber fleece to said base fabric withstitching threads with filaments of material having different thermalcharacteristics, at least one filament material component having a lowerthermal softening range than another filament component of saidstitching thread, and following said stitching, subjecting the resultantcompound fabric to a heat treatment at a temperature at which thefilament material component having the lower softening range becomesheat bondable and fuses to the threads and fibers in contact therewith.

2. The method of claim 1 further comprising stitching a filamentcomponent with said stitching thread which shrinks in the softeningrange of the heat bondable fila ment material component.

3. The method of claim 1 wherein said step of stitching, comprisesstitching a mixed polymeric bicomponent or bi-constituent filamentmaterial, the component having the lower thermal stability being heatbondable within said range and the other component having heatshrinkable characteristics within said range.

2. The method of claim 1 further comprising stitching a filamentcomponent with said stitching thread which shrinks in the softeningrange of the heat bondable filament material component.
 3. The method ofclaim 1 wherein said step of stitching comprises stitching a mixedpolymeric bi-component or bi-constituent filament material, thecomponent having the lower thermal stability being heat bondable withinsaid range and the other component having heat shrinkablecharacteristics within said range.